Chem
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KAIST Develops New Technique for Chiral Activity in Molecules
Professor Hyunwoo Kim of the Chemistry Department and his research team have developed a technique that can easily analyze the optical activity of charged compounds by using nuclear magnetic resonance (NMR) spectroscopy. The research finding entitled “H NMR Chiral Analysis of Charged Molecules via Ion Pairing with Aluminum Complexes” was published online in the October 19th issue of The Journal of the American Chemical Society.
The technique relies on observation of the behavior of optical isomers. Molecules with the same composition that are mirror images of each other are optical isomers. For example, the building blocks of all living organisms, amino acids, are a single optical isomer. In our bodies, optical isomers bring different physiological changes due to their distinct optical activities. Therefore, controlling and analyzing the optical activities are critical when developing a new drug.
High-performance liquid chromatography (HPLC) is the de facto standard of analyzing the optical activity of a compound. However, HPLC is very expensive that many laboratories can’t afford to have. In addition, with the machine, one analysis may take 30 minutes to one hour to complete. It lacks in signal sensitivity and chemical decomposition, and the application is limited to nonpolar compounds.
Usually adopted in analyzing the structure of a chemical compound, NMR spectroscopy requires only one to five minutes per single analysis. Since it is essential for analyzing the molecular structure, many chemistry labs have NMR equipment. However, until this technique was invented, no other research team had reported an effective way of using the NMR spectroscopy to decompose the signal of chiral activity of a compound.
The research team uses negatively-charged metal compounds in NMR spectroscopy. The technique employs negatively-charged metal compounds which bond ionically to positively- and negatively-charged optical compounds. As a result, the NMR spectroscopy can distinguish the signal from chiral activity. Not only can it analyze various chemicals without structural constraints, but it can also be used for both nonpolar and polar solvents.
As many compounds for new drugs have functional groups, which can be charged, this analysis method can be directly employed in the development process of drugs. Professor Kim said, “A revolutionary analysis method has been developed using simple chemical principles. I hope that our method will be applied to the development of new medicine.”
This research was sponsored by the Center for Nanomaterials and Chemical Reactions at the Institute for Basic Science and the Supercomputing Research Center of KAIST.
Picture 1: Separations of NMR Signals of Chemicals due to Interaction with Metal Compounds
Picture 2: Separations of NMR Signals in Different Chemicals
2015.11.20 View 10894 -
Using Light to Treat Alzheimer's Disease
Medical application of photoactive chemicals offers a promising therapeutic strategy for neurodegenerative diseases.
A research team jointly led by Professor Chan Beum Park of the Materials Science and Engineering Department at KAIST and Dr. Kwon Yu from the Bionano Center at the Korea Research Institute of Bioscience and Biotechnology (KRIBB) conducted research to suppress an abnormal assembly of beta-amyloids, a protein commonly found in the brain, by using photo-excited porphyrins.
Beta-amyloid plaques are known to cause Alzheimer's disease. This research finding suggests new ways to treat neurodegenerative illnesses including Alzheimer's disease. It was published online as the lead article in the September 21th issue of Angewandte Chemie. The title of the article is “Photo-excited Porphyrins as a Strong Suppressor of ß-Amyloid Aggregation and Synaptic Toxicity.”
Light-induced treatments using organic photosensitizers have advantages to managing the treatment in time and area. In the case of cancer treatments, doctors use photodynamic therapies where a patient is injected with an organic photosensitizer, and a light is shed on the patient’s lesion. However, such therapies had never been employed to treat neurodegenerative diseases.
Alzheimer's starts when a protein called beta-amyloid is created and deposited in a patient’s brain. The abnormally folded protein created this way harms the brain cells by inducing the degradation of brain functions, for example, dementia. If beta-amyloid creation can be suppressed at an early stage, the formation of amyloid deposits will stop. This could prevent Alzheimer’s disease or halt its progress.
The research team effectively prevented the buildup of beta-amyloids by using blue LED lights and a porphyrin inducer, which is a biocompatible organic compound. By absorbing light energy, a photosensitizer such as porphyrin reaches the excitation state. Active oxygen is created as the porphyrin returns to its ground state. The active oxygen oxidizes a beta-amyloid monomer, and by combining with it, disturbs its assembly.
The technique was tested on drosophilae or fruit flies, which were produced to model Alzheimer on invertebrates. The research showed that symptoms of Alzheimer's disease in the fruit flies such as damage on synapse and muscle, neuronal apoptosis, degradation in motility, and decreased longevity were alleviated. Treatments with light provide additional benefits: less medication is needed than other drug treatments, and there are fewer side effects. When developed, photodynamic therapy will be used widely for this reason.
Professor Park said, “This work has significance as it was the first case to use light and photosensitizers to stop deposits of beta-amyloids. We plan to carry the research further by testing compatibility with other organic and inorganic photosensitizers and by changing the subject of photodynamic therapy to vertebrate such as mice.”
Picture 1 – Deposits of Beta-Amyloid in Fruit Flies Stopped by Using Porphyrin and Blue LED Lights
Picture 2 – The Research Finding Published as the Lead Article in Angewandte Chemie (September 2015)
2015.11.11 View 10557 -
KAIST and Hanwha Chemical Agree on Research Collaboration
KAIST signed a memorandum of understanding (MOU) with Hanwha Chemical Co., Ltd., a Korean chemical and auto manufacturer, on November 2, 2015 to establish a research center on campus.
The research center, which will be named “KAIST-Hanwha Chemical Future Technology Research Center,” will implement joint research projects for five years beginning from 2016 to develop innovative, green technologies that will help the Korean chemical industry boost its global competitiveness and to nurture top researchers and engineers in chemical engineering.
The research center will lead the development of next-generation petrochemical materials and manufacturing technology and the establishment of pure high-refining processes which are more energy-efficient and environmentally friendly. KAIST and Hanwha will strive to secure new technologies that have the greatest commercialization potential in the global market. They will also establish a scholarship fund for 15 KAIST doctoral students in the Department of Chemical and Biomolecular Engineering.
Many professors from the Chemical and Biomolecular Engineering Department including Distinguished Professor Sang Yup Lee, who was listed in the Top 20 Translational Researchers of 2014 by Nature Biotechnology this year, and Professor Hyunjoo Lee who received the Woman Scholar award at the 2015 World Chemistry Conference, will work at the research center.
Professor Lee, the head of the research center, said, “Collaborating with Hanwha will give us a strong basis for our efforts to carry out original research and train the best researchers in the field.”
Chang-Bum Kim, the Chief Executive Officer (CEO) of Hanwha Chemical, said,
“We hope our collaborations with KAIST will go beyond the typical industry and university cooperation. The two organizations will indeed jointly operate the research center, and this will become a new model for industry and university cooperation. We expect that the research center will play a crucial role in the development of new products and technologies to grow the Korean chemical industry.”
In the photo, President Steve Kang of KAIST (fourth from left) and CEO Chang-Bum Kim of Hanwha Chemical (fifth from left) hold the MOU together.
2015.11.01 View 9830 -
Professors Sukbok Chang and Jang-Wook Choi Receive the 2015 Knowledge Award from the Korean Government
The Ministry of Science, ICT and Future Planning (MISP) of the Republic of Korea announced the 2015 Knowledge Awards on October 20, 2015. Two KAIST professors received the award.
Established in 2009, the awards are presented to Korean scientists whose publications have contributed to the international science community. Specifically, the MISP used the two biggest science databases, Science Citation Index Expanded (SCIE) and Scopus, to identify ten highly cited papers ranked in the top 1% by total citations in the past ten years.
Professor Sukbok Chang of Chemistry (left in the picture below) is a global authority in the field of catalytic hydrocarbon functionalization. His paper entitled “Palladium-catalyzed C-H Functionalization of Pyridine N-Oxides: Highly Selective Alkenylation and Direct Arylation with Unactivated Arenes,” which was published in the Journal of the American Chemical Society in 2008, was once selected by Thomson Reuters as one of the “Most Influential Research Papers of the Month.” In 2011, the American Chemical Society included his paper in the list of the top 20 research papers that were most frequently cited in the last three years.
Professor Jang-Wook Choi of the Graduate School of EEWS (Energy, Environment, Water, and Sustainability) has been known for his leading research in rechargeable battery, supercapacitor, and materials chemistry. In particular, his work on secondary fuel cells attracted significant attention from academia and industry in Korea. Professor Choi developed a super-thin flexible lithium-ion battery this year, thinner than a credit card, which lasts longer than the existing batteries and with greater performance. He also developed new electrode materials for next-generation sodium-ion and magnesium secondary fuel cells.
Professor Sukbok Chang (left) and Professor Jang-Wook Choi (right)
2015.10.23 View 9957 -
Affordable Genetic Diagnostic Technique for Target DNA Analysis Developed
Professor Hyun-Gyu Park of the Department of Chemical and Biomolecular Engineering at KAIST has developed a technique to analyze various target DNAs using an aptamer, a DNA fragment that can recognize and bind to a specific protein or enzyme. This technique will allow the development of affordable genetic diagnoses for new bacteria or virus, such as Middle Ease Respiratory Syndrome (MERS). The research findings were published in the June issue of Chemical Communications, issued by the Royal Society of Chemistry in the United Kingdom. The paper was selected as a lead article of the journal.
The existing genetic diagnosis technique, based on molecular beacon probes, requires a new beacon probe whenever a target DNA mutates. As a result, it was costly to analyze various target DNA fragments. To address this problem, Professor Park’s team designed an aptamer that binds and deactivates DNA polymerase. The technique was used in reverse, so that the aptemer did not bind to the polymerase, maintaining its activated state, only if the target DNA was present. These probes are called TagMan probes.
The controlled activation and deactivation of DNA polymerase enables nucleic acid to elongate or dwindle, making it possible to measure fluorescence signals coming from TaqMan probes. This same probe can be used to detect various target DNAs, leading to the development of a new and sensitive genetic diagnostic technique.
Unlike the existing molecular beacon probe technique which requires a new probe for every target DNA, this new technique uses the same fluorescent TaqMan probe, which is cheaper and easier to detect a number of different target nucleic acid fragments. The application of this technique will make the process of identifying and detecting foreign DNAs from pathogens such as virus and bacteria more affordable and simple.
Professor Park said, “This technique will enable us to develop simpler diagnostic kits for new pathogens, such as MERS, allowing a faster response to various diseases. Our technology can also be applied widely in the field of genetic diagnostics.”
Picture: A schematic image of target nucleic acid extracted through the activation and deactivation of DNA polymerase
2015.07.31 View 9596 -
3D Plasmon Antenna Capable of Focusing Light into Few Nanometers
Professors Myung-Ki Kim and Yong-Hee Lee, both of the Physics Department at KAIST, and their research teams have developed a three dimensional (3D) gap-plasmon antenna which can focus light into a space a few nanometers wide. Their research findings were published in the June 10th issue of Nano Letters.
Focusing light into a point-like space is an active research field with many applications. However, concentrating light into a smaller space than its wavelength is often hindered by diffraction. To tackle this problem, many researchers have utilized the plasmonic phenomenon of a metal where light can be confined to a greater extent by overcoming the diffraction limit.
Many researchers have focused on developing a two dimensional (2D) plasmon antenna and were able to focus a light under 5 nanometers wide. However, this 2D antenna revealed a challenge: the light disperses to the opposite end regardless of how small its beam was focused. To solve this difficulty, a 3D structure had to be employed to maximize the light's intensity.
Adopting the proximal focused-ion-beam milling technology, the KAIST research team developed a 3D four nanometer wide gap-plasmon antenna. By squeezing the photons into a 3D nano space of 4 x 10 x 10 nm3 size, the researchers were able to increase the intensity of light by 400,000 times stronger than that of the incident light. Capitalizing on the enhanced intensity of light within the antenna, they intensified the second-harmonic signal and verified that the light was focused in the nano gap by scanning cathodoluminescent images.
The researchers anticipate that this technology will improve the speed of data transfer and processing up to the level of a terahertz (one trillion times per second) and to enlarge the storage volume per unit area on hard disks by 100 times. In addition, high definition images of submolecule size can be taken with actual light, instead of with an electron microscope, while improving the semiconductor process to a smaller size of few nanometers.
Professor Kim said, “A simple yet ingenious idea has shifted the research paradigm from 2D gap-plasmon antennas to 3D antennas. This technology will see numerous applications including in the field of information technology, data storage, imaging medical science, and semiconductor processes.”
The research was sponsored by the National Research Foundation of Korea.
Figure 1: 3D Gap-Plasmon Antenna Structure and Simulation Results
Figure 2 – Constructed 3D Gap-Plasmon Antenna Structure
Figure 3 – Amplified Second Harmonic Signal Generation and Light Focused in the Nano Gap
2015.06.24 View 9696 -
KAIST Team Develops Flexible PRAM
Phase change random access memory (PRAM) is one of the strongest candidates for next-generation nonvolatile memory for flexible and wearable electronics. In order to be used as a core memory for flexible devices, the most important issue is reducing high operating current. The effective solution is to decrease cell size in sub-micron region as in commercialized conventional PRAM. However, the scaling to nano-dimension on flexible substrates is extremely difficult due to soft nature and photolithographic limits on plastics, thus practical flexible PRAM has not been realized yet.
Recently, a team led by Professors Keon Jae Lee and Yeon Sik Jung of the Department of Materials Science and Engineering at KAIST has developed the first flexible PRAM enabled by self-assembled block copolymer (BCP) silica nanostructures with an ultralow current operation (below one quarter of conventional PRAM without BCP) on plastic substrates. BCP is the mixture of two different polymer materials, which can easily create self-ordered arrays of sub-20 nm features through simple spin-coating and plasma treatments. BCP silica nanostructures successfully lowered the contact area by localizing the volume change of phase-change materials and thus resulted in significant power reduction. Furthermore, the ultrathin silicon-based diodes were integrated with phase-change memories (PCM) to suppress the inter-cell interference, which demonstrated random access capability for flexible and wearable electronics. Their work was published in the March issue of ACS Nano: "Flexible One Diode-One Phase Change Memory Array Enabled by Block Copolymer Self-Assembly."
Another way to achieve ultralow-powered PRAM is to utilize self-structured conductive filaments (CF) instead of the resistor-type conventional heater. The self-structured CF nanoheater originated from unipolar memristor can generate strong heat toward phase-change materials due to high current density through the nanofilament. This ground-breaking methodology shows that sub-10 nm filament heater, without using expensive and non-compatible nanolithography, achieved nanoscale switching volume of phase change materials, resulted in the PCM writing current of below 20 uA, the lowest value among top-down PCM devices. This achievement was published in the June online issue of ACS Nano: "Self-Structured Conductive Filament Nanoheater for Chalcogenide Phase Transition." In addition, due to self-structured low-power technology compatible to plastics, the research team has recently succeeded in fabricating a flexible PRAM on wearable substrates.
Professor Lee said, "The demonstration of low power PRAM on plastics is one of the most important issues for next-generation wearable and flexible non-volatile memory. Our innovative and simple methodology represents the strong potential for commercializing flexible PRAM."
In addition, he wrote a review paper regarding the nanotechnology-based electronic devices in the June online issue of Advanced Materials entitled "Performance Enhancement of Electronic and Energy Devices via Block Copolymer Self-Assembly."
Picture Caption:
Low-power nonvolatile PRAM for flexible and wearable memories enabled by (a) self-assembled BCP silica nanostructures and (b) self-structured conductive filament nanoheater.
2015.06.15 View 14287 -
Anti-Cancer Therapy Delivering Drug to an Entire Tumor Developed
KAIST’s Department of Bio and Brain Engineering Professor Ji-Ho Park and his team successfully developed a new highly efficacious anti-cancer nanotechnology by delivering anti-cancer drugs uniformly to an entire tumor. Their research results were published in Nano Letters online on March 31, 2015.
To treat inoperable tumors, anti-cancer medicine is commonly used. However, efficient drug delivery to tumor cells is often difficult, treating an entire tumor with drugs even more so.
Using the existing drug delivery systems, including nanotechnology, a drug can be delivered only to tumor cells near blood vessels, leaving cells at the heart of a tumor intact. Since most drugs are injected into the bloodstream, tumor recurrence post medication is frequent.
Therefore, the team used liposomes that can fuse to the cell membrane and enter the cell. Once inside liposomes the drug can travel into the bloodstream, enter tumor cells near blood vessels, where they are loaded to exosomes, which are naturally occurring nanoparticles in the body. Since exosomes can travel between cells, the drug can be delivered efficiently into inner cells of the tumor.
Exosomes, which are secreted by cells that exist in the tumor microenvironment, is known to have an important role in tumor progression and metastasis since they transfer biological materials between cells. The research team started the investigation recognizing the possibility of delivering the anti-cancer drug to the entire tumor using exosomes.
The team injected the light-sensitive anti-cancer drug using their new delivery technique into experimental mice. The researchers applied light to the tumor site to activate the anti-cancer treatment and analyzed a tissue sample. They observed the effects of the anti-cancer drug in the entire tumor tissue.
The team’s results establish a ground-breaking foothold in drug delivery technology development that can be tailored to specific diseases by understanding its microenvironment. The work paves the way to more effective drug delivery systems for many chronic diseases, including cancer tumors that were difficult to treat due to the inability to penetrate deep into the tissue.
The team is currently conducting experiments with other anti-cancer drugs, which are being developed by pharmaceutical companies, using their tumor-penetrating drug delivery nanotechnology, to identify its effects on malignant tumors.
Professor Park said, “This research is the first to apply biological nanoparticles, exosomes that are continuously secreted and can transfer materials to neighboring cells, to deliver drugs directly to the heart of tumor.”
Picture: Incorporation of hydrophilic and hydrophobic compounds into membrane vesicles by engineering the parental cells via synthetic liposomes.
2015.04.07 View 11111 -
Polymers with Highly Improved Light-transformation Efficiency
A joint Korean research team, led by Professor Bum-Joon Kim of the Department of Chemical and Biomolecular Engineering at KAIST and Professor Young-Woo Han of the Department of Nanofusion Engineering at Pusan National University, has developed a new type of electrically-conductive polymer for solar batteries with an improved light-transformation efficiency of up to 5%. The team considers it a viable replacement for existing plastic batteries for solar power which is viewed as the energy source of the future.
Polymer solar cells have greater structural stability and heat resistance compared to fullerene organic solar cells. However, they have lower light-transformation efficiency—below 4%—compared to 10% of the latter. The low efficiency is due to the failure of blending among the polymers that compose the active layer of the cell. This phenomenon deters the formation and movement of electrons and thus lowers light-transformation efficiency.
By manipulating the structure and concentration of conductive polymers, the team was able to effectively increase the polymer blending and increase light-transformation efficiency. The team was able to maximize the efficiency up to 6% which is the highest reported ratio.
Professor Kim said, “This research demonstrates that conductive polymer plastics can be used widely for solar cells and batteries for mobile devices.”
The research findings were published in the February 18th issue of the Journal of the American Chemical Society (JACS).
Picture: Flexible Solar Cell Polymer Developed by the Research Team
2015.04.05 View 9937 -
Mystery in Membrane Traffic How NSF Disassembles Single SNAR Complex Solved
KAIST researchers discovered that the protein N-ethylmaleimide-sensitive factor (NSF) unravels a single SNARE complex using one round ATP turnover by tearing the complex with a single burst, contradicting a previous theory that it unwinds in a processive manner.
In 2013, James E. Rothman, Randy W. Schekman, and Thomas C. Südhof won the Nobel Prize in Physiology or Medicine for their discoveries of molecular machineries for vesicle trafficking, a major transport system in cells for maintaining cellular processes. Vesicle traffic acts as a kind of “home-delivery service” in cells. Vesicles package and deliver materials such as proteins and hormones from one cell organelle to another. Then it releases its contents by fusing with the target organelle’s membrane. One example of vesicle traffic is in neuronal communications, where neurotransmitters are released from a neuron. Some of the key proteins for vesicle traffic discovered by the Nobel Prize winners were N-ethylmaleimide-sensitive factor (NSF), alpha-soluble NSF attachment protein (α-SNAP), and soluble SNAP receptors (SNAREs).
SNARE proteins are known as the minimal machinery for membrane fusion. To induce membrane fusion, the proteins combine to form a SNARE complex in a four helical bundle, and NSF and α-SNAP disassemble the SNARE complex for reuse. In particular, NSF can bind an energy source molecule, adenosine triphosphate (ATP), and the ATP-bound NSF develops internal tension via cleavage of ATP. This process is used to exert great force on SNARE complexes, eventually pulling them apart. However, although about 30 years have passed since the Nobel Prize winners’ discovery, how NSF/α-SNAP disassembled the SNARE complex remained a mystery to scientists due to a lack in methodology.
In a recent issue of Science, published on March 27, 2015, a research team, led by Tae-Young Yoon of the Department of Physics at the Korea Advanced Institute of Science and Technology (KAIST) and Reinhard Jahn of the Department of Neurobiology of the Max-Planck-Institute for Biophysical Chemistry, reports that NSF/α-SNAP disassemble a single SNARE complex using various single-molecule biophysical methods that allow them to monitor and manipulate individual protein complexes.
“We have learned that NSF releases energy in a burst within 20 milliseconds to “tear” the SNARE complex apart in a one-step global unfolding reaction, which is immediately followed by the release of SNARE proteins,” said Yoon.
Previously, it was believed that NSF disassembled a SNARE complex by unwinding it in a processive manner. Also, largely unexplained was how many cycles of ATP hydrolysis were required and how these cycles were connected to the disassembly of the SNARE complex.
Yoon added, “From our research, we found that NSF requires hydrolysis of ATPs that were already bound before it attached to the SNAREs—which means that only one round of an ATP turnover is sufficient for SNARE complex disassembly. Moreover, this is possible because NSF pulls a SNARE complex apart by building up the energy from individual ATPs and releasing it at once, yielding a “spring-loaded” mechanism.”
NSF is a member of the ATPases associated with various cellular activities family (AAA+ ATPase), which is essential for many cellular functions such as DNA replication and protein degradation, membrane fusion, microtubule severing, peroxisome biogenesis, signal transduction, and the regulation of gene expression. This research has added valuable new insights and hints for studying AAA+ ATPase proteins, which are crucial for various living beings.
The title of the research paper is “Spring-loaded unraveling of a single SNARE complex by NSF in one round of ATP turnover.” (DOI: 10.1126/science.aaa5267)
Youtube Link: https://www.youtube.com/watch?v=FqTSYHtyHWE&feature=youtu.be
Picture 1. Working model of how NSF/α-SNAP disassemble a single SNARE complex
Picture 2. After neurotransmitter release, NSF disassembles a single SNARE complex using a single round of ATP turnover in a single burst reaction.
2015.03.28 View 10005 -
KAIST Develops a Credit-Card-Thick Flexible Lithium Ion Battery
Since the battery can be charged wirelessly, useful applications are expected including medical patches and smart cards.
Professor Jang Wook Choi at KAIST’s Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and Dr. Jae Yong Song at the Korea Research Institute of Standards and Science jointly led research to invent a flexible lithium ion battery that is thinner than a credit card and can be charged wirelessly.
Their research findings were published online in Nano Letters on March 6, 2015. Lithium ion batteries are widely used today in various electronics including mobile devices and electronic cars. Researchers said that their work could help accelerate the development of flexible and wearable electronics.
Conventional lithium ion batteries are manufactured based on a layering technology, stacking up anodes, separating films, and cathodes like a sandwich, which makes it difficult to reduce their thickness. In addition, friction arises between layers, making the batteries impossible to bend. The coating films of electrodes easily come off, which contributes to the batteries’ poor performance.
The research team abandoned the existing production technology. Instead, they removed the separating films, layered the cathodes and anodes collinearly on a plane, and created a partition between electrodes to eliminate potential problems, such as short circuits and voltage dips, commonly present in lithium ion batteries.
After more than five thousand consecutive flexing experiments, the research team confirmed the possibility of a more flexible electrode structure while maintaining the battery performance comparable to the level of current lithium ion batteries.
Flexible batteries can be applied to integrated smart cards, cosmetic and medical patches, and skin adhesive sensors that can control a computer with voice commands or gesture as seen in the movie “Iron Man.”
Moreover, the team has successfully developed wireless-charging technology using electromagnetic induction and solar batteries.
They are currently developing a mass production process to combine this planar battery technology and printing, to ultimately create a new paradigm to print semiconductors and batteries using 3D printers.
Professor Choi said, “This new technology will contribute to diversifying patch functions as it is applicable to power various adhesive medical patches.”
Picture 1: Medical patch (left) and flexible secondary battery (right)
Picture 2: Diagram of flexible battery
Picture 3: Smart card embedding flexible battery
2015.03.24 View 10737 -
Light Driven Drug-Enzyme Reaction Catalytic Platform Developed
Low Cost Dye Used, Hope for Future Development of High Value Medicinal Products to Treat Cardiovascular Disease and Gastric Ulcers
A KAIST research team from the Departments of Materials Science and Engineering and of Chemical and Biomolecular Engineering, led respectively by Professors Chan Beum Park and Ki Jun Jeong, has developed a new reaction platform to induce drug-enzyme reaction using light.
The research results were published in the journal Angewandte Chemie, International Edition, as the back cover on 12 January 2015.
Applications of this technology may enable production of high value products such as medicine for cardiovascular disease and gastric ulcers, for example Omeprazole, using an inexpensive dye.
Cytochrome P450 is an enzyme involved in oxidative response which has an important role in drug and hormone metabolism in organisms. It is known to be responsible for metabolism of 75% of drugs in humans and is considered a fundamental factor in new drug development.
To activate cytochrome P450, the enzyme must receive an electron by reducing the enzyme. In addition, NADPH (a coenzyme) needs to be present. However, since NADPH is expensive, the use of cytochrome P450 was limited to the laboratory and has not yet been commercialized.
The research team used photosensitizer eosin Y instead of NADPH to develop “Whole Cell Photo-Biocatalysis” in bacteria E. coli. By exposing inexpensive eosin Y to light, cytochrome P450 reaction was catalyzed to produce the expensive metabolic material.
Professor Park said, “This research enabled industrial application of cytochrome P450 enzyme, which was previous limited.” He continued, “This technology will help greatly in producing high value medical products using cytochrome P450 enzyme.”
The research was funded by the National Research Foundation of Korea and KAIST's High Risk High Return Project (HRHRP).
Figure 1: Mimetic Diagram of Electron Transfer from Light to Cytochrome P450 Enzyme via Eosin Y, EY
Figure 2: The back cover of Angewandte Chemie published on 12 January 2015, showing the research results
2015.01.26 View 9603